.bg{
	margin:0 auto;
	width:100%;
	height:150%;
	background-color:#000;
	position:absolute;
	z-index: -1;
	/*background-repeat: no-repeat;
    background-size: cover;*/
	background-repeat: no-repeat;
    background-size: cover;
	background-size:100% 100%;
	background-position: center center;
	background-attachment:fixed;
	}
.bg canvas {
	width:100%;
	height:150%;
	display:inline-block;
	vertical-align:baseline;
	position:relative;
	z-index:-1;
	}
/*圆形滚动条*/
    ::-webkit-scrollbar{/*滚动条宽度*/
    	width: 8px;height: 8px;
    }
    ::-webkit-scrollbar-thumb{/*拖动部分*/
    	background-color: rgba(0,0,0,.3);
    	border-radius: 6px;
    }
    ::-webkit-scrollbar-track{/*背景部分*/
		background-color: #ddd;
		border-radius: 6px;
    }